1. Field of the Invention
The present invention relates generally to thermostat security systems and more specifically to a thermostat security system that is access controlled to prevent unauthorized changing of temperature settings.
2. Description of the Prior Art
There are other thermostat security systems. Typical of these is U.S. Pat. No. 4,133,286 issued to Linton on Jan. 9, 1979.
Another patent was issued to Fodera on Sep. 13, 1983 as U.S. Pat. No. 4,403,646. Yet another U.S. Pat. No. 4,663,951 was issued to Poulin on May 12, 1987 and still yet another was issued on Jun. 27, 1989 to Parker et al. as U.S. Pat. No. 4,843,084.
Another patent was issued to Parker et al. on Nov. 28, 1989 as U.S. Pat. No. 4,884,214. Another patent was issued to Smith et al on Jun. 25, 1996 as U.S. Pat. No. 5,530,230. Another patent was issued to Johnson et al. on Oct. 28, 1997 as U.S. Pat. No. 5,682,475. Another patent was issued to Ratcliffe et al on Nov. 4, 1997 as U.S. Pat. No. 5,682,949. Another patent was issued to Lawrence on May 1, 2001 as U.S. Pat. No. 6,223,993 B1. Another patent was issued to Kline et al. on Jun 5, 2001 as U.S. Pat. No. 6,241,156 B1. Another patent was issued to Natale et al. on Jul. 17, 2001 as U.S. Pat. No. 6,260,765 B1.
An adjustable thermostat as disclosed having an adjustment stem journaled for rotation on the thermostat body for adjusting the operating temperature of the thermostat. Mounted on the adjusting stem is a pointer member formed of deformable material such as Nylon and providing a peripheral surface which engages with interference stationary surfaces on the thermostat body. Interengagement is provided between the peripheral surface and the stationary surfaces which causes deformation of the pointer member and creates friction resisting rotation of the pointer and of the adjusting stem. A detent-like structure is provided by flats formed on the peripheral surface of the pointer which mate with the corresponding surfaces of the body to tend to lock the pointer and in turn adjusting stem at a predetermined temperature.
A thermostat device for motels/hotels requiring the guest use a key to select a desired room temperature which in turn requires that the thermostat must be set back to a preset temperature when guest desires to lock the door to his motel/hotel room upon leaving the room.
A security device for a thermostat comprising a housing for said thermostat, a lid member secured to the housing for movement between an opened position and a closed position, to gain and prevent access to the thermostat, respectively. The thermostat has a rotatable thermostat adjustment shaft extending exteriorly of the housing for manual manipulation thereof. A lock member is mounted in the housing for movement between a first position whereat the lock member lockingly engages the adjustment shaft to prevent rotation thereof and engages the lid member to prevent opening thereof and a second position whereat the lock member is disengaged from the adjustment shaft and the lid member permitting manual manipulation of the shaft or opening of the lid member and a key-operated actuating member disposed in the housing and extending exteriorly of the housing for displacing the lock member between its first and second positions.
A microcomputer-controlled thermostat for use in monitoring and controlling a single zone HVAC system which provides conditioned air to one or more zones. The thermostat can be programmed and used either as a monitor thermostat to control the HVAC unit alone and/or to control the HVAC unit and its damper in a multiple zone mode. The thermostat is also programmed as a slave thermostat in a master-slave relationship with a monitor thermostat. The microcomputer memory is supplemented with additional ROM containing control algorithms for use in system operation. Logic circuitry is used to recognize commands as being for operation of the HVAC unit, the operation of the damper, or selection of which systems sensors are to be enabled. A real time clock circuit in the monitor thermostat is used to supply data for time-based system operation.
A microcomputer-controlled thermostat for use in monitoring and controlling a single zone HVAC system which provides conditioned air to one or more zones. The thermostat can be programmed and used either as a monitor thermostat to control the HVAC unit alone and/or to control the HVAC unit and its damper in a multiple zone mode. The thermostat is also programmed as a slave thermostat in a master-slave relationship with a monitor thermostat. The microcomputer memory is supplemented with additional ROM containing control algorithms for use in system operation.
A new variable password safety interlock system for microwave ovens and other computerized or electrical appliance allows the user to dynamically and automatically generate a new password immediately prior to each use. The variable password comprises some prearranged transposition or combination of numbers of digits that were already entered into the microwave control panel by the user. The user first enters digits representing the microwave time, the target food temperature, the microwave power level, the actual time of day on display or some other required combination of digits or microwave console buttons, and then presses the xe2x80x9cStartxe2x80x9d button. The new value of the variable password for that use of the microwave will be some prearranged transposition or combination of the digits, numbers or buttons that had just previously been pressed by the user and that appeared on the microwave control panel at the moment the user pressed the xe2x80x9cStartxe2x80x9d button. Preferably, the password is the digits of the microwave heating time just entered by the user but in reverse order. The password does not require memorization and is easy for the user to compute because the numbers are on display to the user. This password safety interlock is child-proof because a young child will be unable to compute the ephemeral and varying password needed to operate the microwave.
A method and system are provided for controlling access to a data processing system through the use of a variable password. In one embodiment, the invention substitutes the value of a variable into an expression contained in a predefined password, evaluates the expression and password, and compares the result of the valuation of the password to a character string input to the data processing system, granting access if they are identical. A range of values of certain characters of the password may be permitted. The password may require that certain characters be entered within a defined time interval measured from the entry of other characters. The values of environment variables, which are referenced by the variable password, may change from time to time, as a function, for example, of the current time or temperature or system utilization.
This document describes an energy management system in which microprocessor based thermostats are used to control individual room temperatures in a multiple room building in accordance with the known occupancy status of the room. The occupancy status information, as well as other control parameters, are transmitted to the thermostats from a central computer program. The control of a heating and cooling appliances is performed by an algorithm running on the electronic thermostat, which performs this function in accordance with these downloaded parameters. The system, allows room occupants to control the temperature of an occupied room within preset limits, automatically limits energy usage in unoccupied rooms, and provides additional facilities for energy management and general building management.
A climate control system is provided including a vacuum pump for generating a vacuum upon actuation. Also included is a thermostat for generating the activation signal upon a current temperature within the associated room being out of a predetermined range. At least one vent assembly is provided including a plurality of vanes pivotally mounted within the frame and having an unbiased open orientation for allowing the flow of air into the associated room and a biased closed orientation for precluding the flow of air into the associated room and a pneumatic servo connected to each of the vanes and in communication with the vacuum pump. The servo is adapted to transfer the vanes of the vent assembly to the closed orientation thereof only upon the receipt of vacuum. Finally, a vacuum valve is connected between the vacuum pump and the servo of the vent assembly. Such vacuum valve is connected to the thermostat for supplying the same with a vacuum during the receipt of the activation signal.
An apparatus and process for individual adjustment of an operating parameter of a plurality of environmental control devices, such as VAV devices in an HVAC system. The process includes the step of connecting at least one of computers for input of a parameter control set point based signal and a unique VA device identifying signal through an Internet website to the plurality of HVAC devices. The computer is, for example, connected to the VAV devices such that the computer can be used to adjust the temperature set point of only one of the plurality of VAV devices, most typically the device located in the same space as the communicating computer. Such computer can be wired or wireless, and use the global computer network website to connect to the VAV devices through a building computer and local area network. In the preferred form, the computers are also capable of retrieving the current temperature set point from the VAV device and the current room air temperature proximate the VAV device, outputting or displaying them on a computer output or display device, and
An apparatus and process for individual adjustment of an operating parameter of a plurality of environmental control devices, such as VAV devices in an HVAC system. The process includes the step of connecting at least one of computers for input of a parameter control set point based signal and a unique VA device identifying signal through an Internet website to the plurality of HVAC devices. The computer is, for example, connected to the VAV devices such that the computer can be used to adjust the temperature set point of only one of the plurality of VAV devices, most typically the device located in the same space as the communicating computer. Such computer can be wired or wireless, and use the global computer network website to connect to the VAV devices through a building computer and local area network. In the preferred form, the computers are also capable of retrieving the current temperature set point from the VAV device and the current room air temperature proximate the VAV device, outputting or displaying them on a computer output or display device, and
A thermostat system for controlling activation of a temperature management system is operable in an energy-savings mode for enhancing energy savings and in a comfort mode for enhancing comfort, where the operating mode is selectable by a user. The thermostat system has operating mode control circuitry which includes (1) a manual mode control operable to cause the operating mode control circuit to switch between the energy-savings and the comfort states when pressed by the user, (2) a wireless receiver for receiving a wireless mode switching signal that causes the operating mode switching circuitry to switch between the energy-savings and the comfort states, and (3) telephone communication circuitry for receiving a telephonic mode switching signal that causes the operating mode switching circuitry to switch between the energy-savings and the comfort states. Thus, the present invention offers at least three convenient ways for the user to switch between energy-savings and comfort modes of operation. A temperature sensor senses the temperature of the air space and produces a sensed temperature signal based on the temperature of the air space. A controller produces an under-temperature signal when the sensed temperature signal indicates that the temperature is less than a minimum temperature and an over-temperature signal when the sensed temperature signal indicates that the temperature is greater than a maximum temperature. When the under-temperature or over-temperature signal is produced, the telephone communication circuitry places a telephone call to a telephone number of a designated receiving telephone to give a warning concerning the over- or under-temperature condition.
A primary object of the present invention is to provide an access controlled thermostat.
Another object of the present invention is to provide an access controlled thermostat designed to protect from unauthorized changing of a thermostat temperature setting.
Yet another object of the present invention is to provide an access controlled thermostat that would be required prior to changing the settings of the temperature.
Still yet another object of the present invention is to provide a thermostat with password security that the password may be changed at any time by the operator using a master code.
Yet another object of the present invention is to provide a thermostat with password security that temporary password codes can be issued to other people that are only valid for a pre-determined amount of time.
Yet another object of the present invention is to provide a thermostat system that includes a biometric reading device that require biometric input to gain access to the thermostat for changing the temperature setting.
Another object is to provide a thermostat that can respond to keyed manipulation of a lock mechanism if pre-authorized by the operator using the master code in the authorization process.
Additional objects of the present invention will appear as the description proceeds.
The present invention overcomes the shortcomings of the prior art by providing a thermostat access system that is programmed by an operator with a master code to include the optimal types of thermostat access that is dictated by the circumstances. The master code allows the operator to set the system to take passwords, biometric readings, or a lock and key mechanism to access the thermostat to change the temperature setting. If only one method is appropriate at a particular time, the operator can limit the system to accept only that method of access. If a different method is more applicable on a different occasion the operator with the master code can enable only that different method. Passwords can be ongoing until deliberately terminated, or can be temporary with a programmed duration before automatic invalidation.
A system is provided for a user to control a thermostat temperature setting, comprising: a housing component enclosing the thermostat, the housing and thermostat being positioned on a hand-accessible wall; at least one display component for displaying temperature information and control information, the temperature information including at least the actual temperature, the control information including at least prompts and messages; an access controller component having: a plurality of user-operated keys, the keys including at least a plurality of numeric keys; a memory for storing and accessing information entered by the user, the information including at least a master code and a password; the access controller component being operative to: accept a password, the password being keyed in by the user, the display then prompting the user to key in a new thermostat temperature setting if the password matches a password stored in the memory; reject a keyed in password if said password does not match a stored password, the display communicating the rejection; communicate the keyed in new thermostat temperature setting to the thermostat, the thermostat being adapted to adjust the temperature setting in response to the communication; and accept a keyed in master code if the keyed in master code matches the master code stored in the memory, the display then prompting the master code user to key in the user""s choice of the access controller component functions the user desires to modify, and further prompting for keyed in entries to make those modifications, the available modifications at least including: modifying the acceptable passwords by adding new passwords or eliminating then stored passwords; and reject a keyed in master code if the keyed in master code does not match the master code stored in the memory.
A system is provided for a user to control a thermostat temperature setting, comprising: a housing component enclosing the thermostat, the housing and thermostat being positioned on a hand-accessible wall; at least one display component for displaying temperature information and control information, the temperature information including at least the actual temperature, the control information including at least prompts and messages; an access controller component having: a plurality of user-operated keys, the keys including at least a plurality of numeric keys; a biometric reading device for receiving biometric information from the user; a memory for storing and accessing information entered by the user, the information including at least a master code, a password, and a biometric record of the user; the access controller component being operative to: accept a password, the password being keyed in by the user, the display then prompting the user to key in a new thermostat temperature setting if the password matches a password stored in the memory; reject a keyed in password if said password does not match a stored password, the display communicating the rejection; accept a biometric reading and compare the reading to the stored biometric record, the display then prompting the user to key in a new thermostat temperature setting if the biometric reading matches a biometric record stored in the memory; reject a biometric reading if said reading does not match the stored biometric record of the user, the display communicating the rejection; communicate the keyed in new thermostat temperature setting to the thermostat, the thermostat being adapted to adjust the temperature setting in response to the communication; and accept a keyed in master code if the keyed in master code matches the master code stored in the memory, the display then prompting the master code user to key in the user""s choice of the access controller component functions the user desires to modify, and further prompting for keyed in entries to make those modifications, the available modifications at least including: modifying the acceptable passwords by adding new passwords or eliminating then stored passwords; and modifying the biometric record by adding new biometric records or eliminating then stored biometric records; reject a keyed in master code if the keyed in master code does not match the master code stored in the memory.
In another embodiment, modification of acceptable passwords includes at least the options of: adding a new password; eliminating a stored password; adding a temporary password, and information determining its duration; and eliminating a temporary password, and information determining its duration.
In another embodiment, the available modification to the master code user also includes: setting the time; setting the date; and setting a schedule wherein the thermostat temperature setting is adjusted at various times and dates keyed-in by the master code user.
In another embodiment, the access controller component has a clearing key that, when depressed, restores the system to the un-accessed status.
In another embodiment, the access controller component is further operative to prompt for a keyed-in selection of the user""s choice of password access or biometric access.
In another embodiment, the access controller component further comprises a general access key that, when depressed causes the access controller component to prompt for a keyed-in selection of the user""s choice of password access or biometric access.
In another embodiment, the access controller component further comprises a master access key that, when depressed causes the access controller component to prompt for the master code to be keyed-in.
In another embodiment, the access controller component biometric reading is a thumb print, the access controller component having a biometric reading device for the thumb to contact, the device reading the thumb print and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component biometric reading is a finger print, the access controller component having a biometric reading device for the finger to contact, the device reading the finger print and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component biometric reading is a retinal scan, the access controller having a biometric reading device into which the user""s close gaze is directed, the device reading the retinal scan and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component biometric reading is an iris scan, the access controller having a biometric reading device into which the user""s close gaze is directed, the device reading the iris scan and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component biometric reading is a voice pattern, the access controller having a biometric reading device into which the user""s voice is directed, the device reading the voice pattern and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component biometric reading is a facial image, the access controller having a biometric reading device at which the user""s face is presented, the device reading the facial image and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component also has a lock mechanism and a key for manipulating the lock mechanism, the stored and accessible memory information includes an on or off status for the lock mechanism, and the access controller component is operative to: accept a keyed manipulation of the lock mechanism if the stored lock mechanism information indicates the lock mechanism is on, the display then prompting the user to key in a new thermostat temperature setting; and reject a keyed manipulation of the lock mechanism if the stored information indicates the lock mechanism is off, the display communicating the rejection.
In another embodiment, the available modifications to the master code user also includes changing the on or off status for the lock mechanism.
In another embodiment, the access controller component further comprises a general access key that, when depressed causes the access controller component to prompt for a keyed-in selection of the user""s choice of password access, biometric access, or key access.
A system is provided for a user to control a thermostat temperature setting, comprising: a housing component enclosing the thermostat, the housing and thermostat being positioned on a hand-accessible wall; display means for displaying temperature information and control information, the temperature information including at least the actual temperature, the control information including at least prompts and messages; access control means for controlling access to the thermostat, the access control means having: a plurality of user-operated keys, the keys including at least a plurality of numeric keys; biometric reading means for receiving biometric information from the user; memory means for storing and accessing information entered by the user, the information including at least a master code, at least one password, and a biometric record of the user; the access control means being operative to: accept a password, the password being keyed in by the user-operable keys, the display means then prompting the user to key in a new thermostat temperature setting if the password matches a password stored in the memory; reject a keyed in password if said password does not match a stored password, the display means communicating the rejection; accept a biometric reading and compare the reading to the stored biometric record, the display means then prompting the user to key in a new thermostat temperature setting if the biometric reading matches a biometric record stored in the memory; reject a biometric reading if said reading does not match a stored biometric record of the user, the display means communicating the rejection; communicate the keyed in new thermostat temperature setting to the thermostat, the thermostat being adapted to adjust the temperature setting in response to the communication; accept a keyed in master code if the keyed in master code matches the master code stored in the memory, the display means then prompting the master code user to key in the user""s choice of the access controller function the user desires to modify, and further prompting for keyed in entries to make those modifications, the available modifications at least including: modifying the acceptable passwords by adding new passwords or eliminating then stored passwords; and modifying the biometric record by adding new biometric records or eliminating then stored biometric records; reject a keyed in master code if the keyed in master code does not match the master code stored in the memory.
In another embodiment, modification of acceptable passwords includes at least the options of: adding a new password; eliminating a stored password; adding a temporary password, and information determining its duration; and eliminating a temporary password, and information determining its duration.
In another embodiment, the available modification to the master code user also includes: setting the time; setting the date; and setting a schedule wherein the thermostat temperature setting is adjusted at various times and dates keyed-in by the master code user.
In another embodiment, the access control means has a clearing key that, when depressed, restores the system to the un-accessed status.
In another embodiment, the access control means is further operative to prompt for a keyed-in selection of the user""s choice of password access or biometric access.
In another embodiment, the access control means further comprises a general access key that, when depressed causes the access control means to prompt for a keyed-in selection of the user""s choice of password access or biometric access.
In another embodiment, the access control means further comprises a master access key that, when depressed causes the access control means to prompt for the master code to be keyed-in.
In another embodiment, the access control means biometric reading is a thumb print, the access control means having a biometric reading device for the thumb to contact, the device reading the thumb print and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access control means biometric reading is a finger print, the access control means having a biometric reading device for the finger to contact, the device reading the finger print and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access control means biometric reading is a retinal scan, the access controller having a biometric reading device into which the user""s close gaze is directed, the device reading the retinal scan and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access control means biometric reading is an iris scan, the access controller having a biometric reading device into which the user""s close gaze is directed, the device reading the iris scan and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access control means biometric reading is a voice pattern, the access controller having a biometric reading device into which the user""s voice is directed, the device reading the voice pattern and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access controller component biometric reading is a facial image, the access controller having a biometric reading device at which the user""s face is presented, the device reading the facial image and communicating the biometric reading for the comparison to the biometric record.
In another embodiment, the access control means also has a lock mechanism and a key for manipulating the lock mechanism, the stored and accessible memory information includes an on or off status for the lock mechanism, and the access control means is operative to: accept a keyed manipulation of the lock mechanism if the stored lock mechanism information indicates the lock mechanism is on, the display means then prompting the user to key in a new thermostat temperature setting; reject a keyed manipulation of the lock mechanism if the stored information indicates the lock mechanism is off, the display means communicating the rejection.
In another embodiment, the available modifications to the master code user also includes changing the on or off status for the lock mechanism.
In another embodiment, the access control means further comprises a general access key that, when depressed causes the access control means to prompt for a keyed-in selection of the user""s choice of password access, biometric access, or key access.
A method is provided to control access to a thermostat at least one user in accordance with parameters set by of an operator, the thermostat being enclosed in a housing, and a controller being in electronic communication with the thermostat, in electronic communication with at least one display for displaying alphanumeric characters, and in electronic communication with user-operable keys, the controller being programmable and having a memory, the method comprising the steps of: accepting a master code as entered by the operator using the keys; allowing access to the controller memory if the master code is valid; accepting the operator""s choice of one function from a plurality of functions for which function parameters are to be changed, including at least the functions of setting a permanent password, setting a temporary password and its duration parameters, and setting biometric access parameters; if the operator chose setting a permanent password, prompting for keypad entry of at least one permanent password; accepting the operator""s keypad entry of the at least one permanent password and storing the at least one permanent password in the memory; if the operator chose setting a temporary password, prompting for keypad entry of at least one temporary password and duration determinative keypad entries for each of the at least one temporary passwords; accepting the operator""s keypad entry of the at least one temporary password and duration determinative entries and storing the at least one temporary password and duration determinative entries in the memory; if the operator chose setting biometric reading parameters, prompting for a biometric reading of a biometric characteristic of the at least one intended user; accepting the biometric reading and storing the biometric reading in the memory as a biometric record; controlling access to keypad entry of a thermostat temperature setting by a user by: accepting the user""s keypad entry of a password, if the entered password matches a stored permanent or temporary password, then accepting a keypad entry of a new thermostat temperature setting; rejecting the user""s keypad entry of a password, if the entered password does not match either a stored permanent or temporary password, then displaying the rejection; accepting the user""s provision of a biometric reading, if the biometric reading matches a stored biometric record, then accepting a keypad entry of a new thermostat temperature setting; rejecting the user""s provision of a biometric reading, if the biometric reading does not match a stored biometric record.
In another embodiment, a lock mechanism is in electronic communication with the controller and the functions for which parameters are changeable by the operator also include setting the controller to accept or reject a keyed manipulation of a lock mechanism such that the controller accepts a keyed manipulation of the lock mechanism by the user if the operator has set the controller to accept the same, and rejects the keyed manipulation of the lock mechanism by the user if the operator has set the controller to reject the same.
In another embodiment, the functions for which parameters are changeable by the operator also include: setting the time; setting the date; and setting a schedule wherein the thermostat temperature setting is adjusted at various times and dates keyed-in by the operator.
A system is provided for a user to control a thermostat temperature setting, comprising: a housing component enclosing the thermostat, the housing and thermostat being positioned on a hand-accessible wall; at least one display component for displaying temperature information and control information, the temperature information including at least the actual temperature, the control information including at least prompts and messages; an access controller component having: a plurality of user-operated keys, the keys including at least a plurality of numeric keys; a biometric reading device for receiving biometric information from the user; a lock mechanism and a key for manipulating the lock mechanism, the stored and accessible memory information includes an on or off status for the lock mechanism; a memory for storing and accessing information entered by the user, the information including at least a master code, a password, a biometric record of the user, an on or off status for the lock mechanism, a system time, a system date, a system schedule; the access controller component being operative to: accept a password, the password being keyed in by the user, the display then prompting the user to key in a new thermostat temperature setting if the password matches a password stored in the memory; reject a keyed in password if said password does not match a stored password, the display communicating the rejection; accept a biometric reading and compare the reading to the stored biometric record, the display then prompting the user to key in a new thermostat temperature setting if the biometric reading matches a biometric record stored in the memory; reject a biometric reading if said reading does not match the stored biometric record of the user, the display communicating the rejection; accept a keyed manipulation of the lock mechanism if the stored lock mechanism information indicates the lock mechanism is on, the display then prompting the user to key in a new thermostat temperature setting; and reject a keyed manipulation of the lock mechanism if the stored information indicates the lock mechanism is off, the display communicating the rejection; communicate the keyed in new thermostat temperature setting to the thermostat, the thermostat being adapted to adjust the temperature setting in response to the communication; and accept a keyed in master code if the keyed in master code matches the master code stored in the memory, the display then prompting the master code user to key in the user""s choice of the access controller component functions the user desires to modify, and further prompting for keyed in entries to make those modifications, the available modifications at least including: modifying the acceptable passwords by adding new passwords, eliminating then stored passwords, adding a temporary password and information determining its duration; modifying the biometric record by adding new biometric records or eliminating then stored biometric records; and modifying the on or off status of the lock mechanism; modifying the system time; modifying the system date; modifying the system schedule such that the thermostat temperature setting is automatically adjusted at various times and dates; and reject a keyed in master code if the keyed in master code does not match the master code stored in the memory.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawing, like reference characters designate the same or similar parts throughout the several views.
The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.